Latency Constrained Simultaneous Wireless Information and Power Transfer

This paper studies a power splitting (PS)-based simultaneous wireless information and power transfer (SWIPT) multi-user system. Specifically, an optimization problem is formulated to minimize the average transmit power of the base station (BS) by jointly optimizing the transmit beamformer and receive PS ratios, while meeting user-specific latency and energy harvesting (EH) requirements. We employ the Lyapunov optimization framework and provide a dynamic control algorithm for the time-average problem. The coupled and non-convex constraints are handled via the Successive Convex Approximation (SCA) technique, and a low-complexity iterative algorithm, where each step is computed in closed-form, is proposed by solving a system of Karush-Kuhn-Tucker (KKT) optimality conditions. The numerical results provide insights on the robustness of the proposed design to realize a power-efficient SWIPT system while ensuring latency and EH requirements in a dynamic network.